Vertical Velocity Indicator

The Vertical Velocity Indicator (VVI) is a flight instrument that is part of the supply class Flight Instruments in the supply group Instruments And Laboratory Equipment.

The VVI provides the pilot with information about the rate of climb or descent of the aircraft. It measures the vertical speed of the aircraft in feet per minute (or meters per second) and displays it on a dial or digital display.

The VVI is an important instrument for pilots as it helps them maintain a desired rate of climb or descent during various phases of flight, such as takeoff, landing, and level flight. It is particularly useful during instrument flight, where maintaining precise vertical speed is crucial for maintaining proper separation from other aircraft and for following air traffic control instructions.

The VVI typically operates using a pressure sensing mechanism that measures the difference in air pressure between the static pressure outside the aircraft and the static pressure inside the instrument. This pressure difference is then converted into a vertical speed indication.

In addition to the rate of climb or descent, some VVI instruments may also provide additional information such as a trend indicator, which shows whether the aircraft is accelerating or decelerating in the vertical plane.

Overall, the Vertical Velocity Indicator is a vital instrument for pilots, providing them with essential information about the aircraft's vertical speed and aiding in safe and efficient flight operations.